Electrical Connection - Three-Phase Pumps, 11-22 Kw; Preparation; Protection Against Electric Shock - Indirect Contact; Backup Fuses - Grundfos CRE Installation And Operating Instructions Manual

5.3 Electrical connection - three-phase pumps,
11-22 kW
Warning
The user or the installer is responsible for the
installation of correct earthing and protection
according to current national and local
standards. All operations must be carried out by
qualified personnel.
Warning
Never make any connections in the pump
terminal box unless all electric supply circuits
have been switched off for at least 5 minutes.
Note for instance that the signal relay may be
connected to an external supply which is still
connected when the mains supply is
disconnected.
Warning
( ( ( The surface of the terminal box may be above
___
) ) )
70 °C when the pump is operating.

5.3.1 Preparation

Before connecting the E-pump to the mains, take the issues
illustrated in the figure below into consideration.
L1
L2 ELCB
L3
PE
Fig. 8 Mains-connected pump with mains switch, backup
fuses, additional protection and protective earthing

5.3.2 Protection against electric shock - indirect contact

Warning
The pump must be earthed in accordance with
national regulations.
As the leakage current of 11-22 kW motors is
> 10 mA, take extra precautions when earthing
these motors.
EN 61800-5-1 specifies that the pump must be stationary and
installed permanently when the leakage current is > 10 mA.
One of the following requirements must be fulfilled:
• A single protective earth conductor having a cross-sectional
2
area of min. 10 mm copper.
Fig. 9 Connection of a single protective earth conductor
using one of the conductors of a 4-core mains cable
(with cross-sectional area of min. 10 mm
• Two protective earth conductors of the same cross-sectional
area as the mains conductors, with one conductor connected
to an additional earth terminal in the terminal box.
Fig. 10 Connection of two protective earth conductors using
Protective earth conductors must always have a yellow/green
(PE) or yellow/green/blue (PEN) colour marking.

5.3.3 Backup fuses

For recommended fuse sizes, see section 30.

5.3.4 Additional protection

If the pump is connected to an electric installation where an earth
leakage circuit breaker (ELCB) is used as additional protection,
the circuit breaker must be of a type marked with the following
L1
symbols:
L2
L3
This circuit breaker is type B.
The total leakage current of all the electrical equipment in the
installation must be taken into account.
The leakage current of the motor in normal operation can be seen
in section 22.3 Leakage current.
During start and at asymmetrical supply systems, the leakage
current can be higher than normal and may cause the ELCB to
trip.

5.3.5 Motor protection

The pump requires no external motor protection. The motor
incorporates thermal protection against slow overloading and
blocking (IEC 34-11, TP 211).

5.3.6 Protection against mains voltage transients

The pump is protected against mains voltage transients in
accordance with EN 61800-3 and is capable of withstanding a
VDE 0160 pulse.
The pump has a replaceable varistor which is part of the transient
protection.
Over time this varistor will be worn and need to be replaced.
When the time for replacement has come, R100 and
PC Tool E-products will indicate this as a warning. See
19. Maintenance and service.

5.3.7 Supply voltage and mains

3 x 380-480 V –10 %/+10 %, 50/60 Hz, PE.
The supply voltage and frequency are marked on the pump
nameplate. Make sure that the motor is suitable for the electricity
supply of the installation site.
The wires in the terminal box must be as short as possible.
Excepted from this is the protective earth conductor which must
be so long that it is the last one to be disconnected in case the
cable is inadvertently pulled out of the cable entry.
2
)
two of the conductors of a 5-core mains cable
ELCB
11